PROJECTSUMMARY Asaleadingcauseoffatalandnon-fatalinjuriesinolderindividuals,fallsareasignificanthealthconcernand one of the most feared consequences of aging. Although numerous rehabilitation interventions have been developed to improve balance in older adults, these improvements do not effectively reduce the incidence of fallsandfallrelatedinjuries.Moreover,suchinterventionshavebeennearlyexclusivelyfocusedonenhancing lowerlimbresponses,whiletrainingdirectedtowardstheupperlimbiscommonlyoverlooked.Inconfinedareas, such as the bathroom, where the majority of indoor falls occur, lower limb stepping recovery strategies are restricted and movements of the arms to grasp stable surfaces and secure balance or protect against ground impactbecomecrucialtothepreventionofheadtraumaandothermajorinjuries.Anotherkeyconsiderationis thatonlinesensoryinformationdetectingbaseofsupportperturbationssuchasslipsortripsisoftenunreliable withage,potentiallyrenderingareflexivelytriggeredsteppingorprotectivearmresponseineffectiveduetotiming delays, direction errors, or reduced extent. We, and others, have shown an increased use of the reach-grasp responseinoldercomparedtoyoungeradults,butwithmarkedlydecreasedeffectiveness,particularlyamong those who have previously fallen. The overall objective of this proposal is to investigate the effect of attention switchingonreach-graspstabilizingresponsesduringfall-inducedperturbations.Thecentralhypothesisisthat added challenges to attention shifting from internally-directed, highly engaging and stressful thoughts towards externalsensorystimulireflectingbalanceinstabilitywilldelaythetriggeringofreachexecutiontimingandreduce grasping accuracy that will be improved with cognitive-sensorimotor training. This research will mark the first characterization of the role of attention shifting on protective arm responses and fall rate during a balance perturbation paradigm and the first fully integrated cognitive and physical rehabilitation intervention, moving beyond correlative designs and parallel treatments. The overall public health significance of the proposed research is that once the underlying neurocognitive mechanisms to reactive balance responses have been identified,wewillhavethenecessarystepstosupportevaluationofanovelattentionshifting-reactivebalance trainingprogramtoenhancebalanceandpreventfalls.